Liberal reforms allowing female clergy and same-sex marriage are creating a widening gulf within world Christianity, a leading Russian Orthodox bishop said.

That growing divide may prompt Orthodox churches to consider a tactical alliance with Roman Catholicism to defend traditional Christian values, Bishop Hilarion Alfeyev said on the sidelines of the global assembly of the mostly Protestant World Council of Churches (WCC).

While Orthodox churches, with some 220 million members, are members of the WCC, now holding its global assembly in Brazil, Alfeyev – the chief Russian Orthodox delegate – said they have less in common with fellow members than they once had.

“We (Orthodox and Catholics) are on the same side of the divide.” “Traditional Christianity’s very survival is in jeopardy. We have no right to delay this strategic alliance, because in 20-40 years it will be too late,”

Alfeyev, the Bishop of Vienna also in charge of Russian Orthodox Church relations with the European Union, said the alliance should not be a matter of dogma and should precede the resolution of many centuries-old differences between the two oldest branches of Christianity, some dating back to the Great Schism of 1054.